Johnny, of mass 65 kg, and Lucy, of mass 45 kg, are facing each other on roller blades. The coefficient of kinetic friction between the roller blades and concrete surface is 0.20. When Johnny pushes Lucy from rest he applies a force for 1.0 s. Lucy then slows down to a stop in another 8.0 s. Calculate: a.The applied force exerted by Johnny on Lucy. b.How long it takes Johnny to come to rest
Johnny, of mass 65 kg, and Lucy, of mass 45 kg, are facing each other on...
A 30 KG GIRL AND A 25 KG BOY FACE EACH OTHER ON FRICTION-FREE ROLLER BLADES. THE GIRL PUSHES THE BOY, WHO MOVES AWAY AT A SPEED OF 1.0 M/S. THE GIRLS SPEED IS?
A 65-kg ice skater stands facing a wall with his arms bent and then pushes away from the wall by straightening his arms. At the instant at which his fingers lose contact with the wall, his center of mass has moved 0.50 What is the average force exerted by the wall on him? What is the work done by the wall on him? What is the change in the kinetic energy of his center of mass? Express you answers in...
A student pushes a chair of a mass 26.7 kg on a flat surface with no elevation changes at a speed of 10.2 m/s without any acceleration. The coefficient of kinetic friction between the chair's roller and the flat surface is 0.29. What horizontal force (in newtons) does the student applies on the chair to keep it in motion?
You pull a your friend along in a sled (combined mass is 65 kg), by pulling the rope at an upward angle of 20 degrees with respect to the ground with enough force to keep the sled moving at a constant velocity of <3,0, 0> m/s. The coefficient of kinetic friction between the ground and the sled is 0.15. (a) Draw a force diagram for the friend/sled system. (b) Once you get to constant velocity, you pull the sled 15...
Two crates, of mass m1= 50 kg and m2= 100 kg, are in contact and at rest on a horizontal surface. Force F= 600 N is exerted on the 50-kg crate. The coefficient of kinetic friction is 0.20. A) determine the acceleration of the system. B) determine the magnitude of the force that each crate exerts on the other.
A box of mass 40 kg is initially at rest on a flat floor. The coefficient of kinetic friction between the box and the floor is µk = 0.40. A woman pushes against the box with a force of 250 N that makes an angle of 30° with the horizontal until the box attains a speed of 1.0 m/s. (a) What is the change of kinetic energy of the box? (b) What is the work done by the friction force...
1). the roller coaster car with a mass of 250 kg starts with an initial speed v0 = 5.6 m/s at the top of the track . What is its speed (in m/s) at the lowest point of the track (which is 25m below the start point)? Keep 2 decimal places. 1 b) Recall what you learned in vertical circular motion. If the lowest part of the track is approximated as circular with a radius of 6.20 m, What is the...
1. A 3.00 kg mass is initially at rest when it is subjected to an applied force directed in the +x direction and the force of kinetic friction while upon a horizontal surface. The work done by the applied force on the mass is known to be 25.0 J over a particular time interval. a) If the speed of the mass is measured to be 3.50 m/s at the end of the time interval, what is the net work done?...
Consider a 3.0 kg mass on a spring on a horizontal surface. The
spring has spring constant 45 N/m. The static coefficient of
friction between the mass and the surface is µS = 0.30 and the
kinetic coefficient of friction is µK = 0.20
(a) When the mass is at x0 = 20 cm it is moving to the right
with speed 50 cm/s. Where does it first come to a stop? [Hint: use
energy considerations.]
(b) Once the mass...
8. A uniform rod of length 1.0 m and mass 0.80 kg has small 0.30 kg attached to either end. It is made to rotate in a horizontal plane about an axis through its center The system starts from rest and after 8.0 s it is rotating at 5.0 a) What is the object's angular acceleration in ind? 0.30 kg 0.kg 0.30 kg 1.0 m b) How many revolutions did the object make in the 8.0 s it was speeding...